CN114873575A - Sodium ion battery positive electrode material prepared by gel method and preparation method thereof - Google Patents
Sodium ion battery positive electrode material prepared by gel method and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a sodium ion battery anode material prepared by a gel method and a preparation method thereof. The invention relates to a positive electrode material of a sodium ion battery, which is a compound of phosphoric acid and pyrophosphate containing sodium, manganese, iron and metal doping elements. The raw materials used in the invention do not contain noble metals, are cheap and easily available, but can ensure higher gram capacity and high voltage, and can improve the volumetric specific energy of the sodium-ion battery. The preparation method of the material adopts a mature gel method, adopts citric acid as a complexing agent and a gelling agent, can generate a homogeneous precursor, and is free from discharge and pollution in the production process and relatively environment-friendly. The gel is decomposed at high temperature to generate the carbon coating layer in situ, so that the electronic conductivity of the material can be further improved.
Description
Technical Field
The invention relates to the technical field of secondary batteries, in particular to a sodium ion battery anode material prepared by a gel method and a preparation method thereof.
Background
With the development of lithium resources and noble metals such as nickel, cobalt and the like, the production cost of the lithium ion battery is continuously increased, and the popularization and application of new energy vehicles and battery energy storage markets are severely restricted. The battery technology solution with abundant resources, low cost, environmental protection and safe use is still the first problem to be solved by new energy automobiles.
The working principle of the sodium ion battery is basically similar to that of the lithium ion battery, sodium is one of the metal elements which are stored in the earth crust abundantly, and the positive electrode material of the sodium ion battery can adopt cheap elements, so that the sodium ion battery material is one of the technologies with the most development potential.
The research on the positive electrode material of the sodium-ion battery mainly focuses on metal oxides, Prussian blue compounds and polyanion compounds. The metal oxide has low reversible capacity, contains noble metals such as copper, nickel and the like, has high cost and is sensitive to moisture, so that the metal oxide is difficult to apply on a large scale. The Prussian blue compound is used as a sodium ion battery, although the potential is proper, the compaction density is low, the thermal stability is poor, and toxic groups exist in the material. The polyanionic compound takes sodium vanadium phosphate as a representative material, has the advantages of higher voltage, higher theoretical specific capacity, stable structure and the like, is one of the preferred positive electrode materials of the sodium-ion battery, but has poor vanadium resources and toxic vanadium, so the polyanionic compound has larger difficulty in scale application.
For example, the invention application with the application number of CN201711118490.5 discloses a phosphate pyrophosphate complex polyanion type iron-based cathode material with the chemical formula of Na 4 Fe 2 M(PO 4 ) 2 P 2 O 7 Wherein M is at least one of Mn, Co and Ni. Also discloses a preparation method of the positive electrode material of the sodium-ion battery,dissolving a sodium source, an iron source, an M source and a phosphorus source in water according to the proportion of Na, Fe, M and P elements of the chemical formula to obtain a mixed solution; adding a complexing agent into the mixed solution, heating and stirring to obtain gel; drying the gel to obtain a precursor; and calcining the precursor at 450-650 ℃ to obtain the cathode material. The sodium source is preferably a compound that is soluble in aqueous solution and ionizable to release Na +. The sodium source is at least one of sodium pyrophosphate, sodium acetate, sodium nitrate, sodium carbonate, sodium bicarbonate, sodium dihydrogen phosphate and disodium hydrogen phosphate. The iron source is preferably soluble in aqueous solution and ionizable to release Fe 2+ /Fe + The compound of (1). The iron source is at least one of ferrous oxalate, ferric nitrate, ferric citrate and ferric ammonium citrate. The M source is a water-soluble salt of M metal ions. The M source is preferably water-soluble salts of Mn, Co and Ni. More preferably, the manganese source is one or more of manganese acetate, manganese nitrate and manganese oxalate; the cobalt source is one or more of cobalt acetate, cobalt nitrate and cobalt oxalate; the nickel source is one or more of nickel acetate, nickel carbonate and nickel oxalate. The phosphorus source is one or more of ammonium dihydrogen phosphate, phosphoric acid, diammonium hydrogen phosphate, ammonium phosphate, disodium hydrogen phosphate, sodium pyrophosphate and sodium dihydrogen phosphate. The complexing agent is at least one of tetraethylene glycol, ethylene glycol, citric acid, oxalic acid, glucose, sucrose, ascorbic acid, polyvinylpyrrolidone and polyvinyl alcohol. A further preferred complexing agent is tetraethyleneglycol.
Soluble iron salt, sodium salt and M salt are dissolved in water, metal ions are complexed by a complexing agent to form gel, a precursor is obtained by drying, and the anode material is obtained by calcining. The disadvantages of the invention are: the precursor contains a large amount of salts and complexing agents, particularly nitrates, and the precursor is generated in the calcining process as follows: nitrogen monoxide, nitrogen dioxide, carbon dioxide. In the actual preparation process, a large amount of pollutants are generated, and meanwhile, the preparation scheme is not energy-saving and environment-friendly because the organic matter content is high and the energy consumption is high.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a sodium-ion battery positive electrode material prepared by a gel method and a preparation method thereof.
A sodium ion battery positive electrode material prepared by a gel method comprises the following steps:
(1) adding a phosphorus source, a gelling agent and deionized water into a reaction kettle,
wherein the mass ratio of the gelling agent to the phosphorus source is 1-2: 9;
(2) adding an iron source, a manganese source and a doping element source into the reaction kettle in the step (1), and carrying out mixing reaction under the protection of inert atmosphere;
(3) preparing a sodium source into a solution, adding the solution into the reaction kettle reacted in the step (2), and carrying out mixed reaction under the protection of inert atmosphere;
(4) spray drying the reaction product obtained in the step (3) to obtain a precursor, carrying out heat treatment on the precursor under the protection of inert atmosphere to obtain the sodium-ion battery anode material,
wherein the molar ratio of sodium element, manganese element, iron element, doping element source and phosphorus element in the sodium source, manganese source, iron element, doping element and phosphorus source is 4: 0.5-2.5: 0.49-2.07: 0.01-0.04: 3.6-4.
Preferably, the gelling agent is citric acid.
More preferably, 2.27-5.88 g of gelling agent is correspondingly added into every 100ml of deionized water in the step (1).
Preferably, the phosphorus source is at least one of phosphoric acid and ammonium dihydrogen phosphate;
the iron source is at least one of iron powder and ferrous carbonate;
the manganese source is manganese carbonate;
the doping element source is at least one of magnesium hydroxide, aluminum hydroxide, magnesium carbonate and aluminum carbonate;
the sodium source is sodium hydroxide.
Preferably, in the step (2), the feeding time is controlled to be 2-3 h, the reaction time is controlled to be 24-48 h, the reaction temperature is controlled to be 60-80 ℃, and the rotating speed of the reaction kettle is 200-2000 rpm. The phosphorus source and the gelling agent citric acid are firstly added into the reaction kettle to be prepared into solution with the deionized water, and then other raw materials are slowly added in the step (2), so that the phenomenon that the reaction is too violent and is difficult to control is avoided.
Preferably, in the step (3), the molar concentration of the sodium source is controlled to be 1-20 mol/L, the feeding time is controlled to be 30-60 minutes, the reaction temperature is controlled to be 60-80 ℃, and the rotating speed of the reaction kettle is 200-2000 rpm.
Preferably, in the step (4), the temperature of the heat treatment is 500-680 ℃, and the time is 5-20 hours.
Wherein, in each step, the inert atmosphere is argon atmosphere or nitrogen atmosphere.
The invention also provides the positive electrode material of the sodium-ion battery prepared by the preparation method.
The invention also provides application of the sodium-ion battery positive electrode material in preparation of a sodium-ion battery.
The invention has the beneficial effects that:
(1) the positive electrode material of the sodium-ion battery is a phosphoric acid and pyrophosphoric acid double salt compound containing sodium, manganese, iron and metal doping elements, wherein the active elements are Mn and Fe, and the Mn element is characterized by comprising the following components in percentage by weight: high potential and high capacity, and has the defects of poor electronic conductivity and short service life; the Fe element is characterized by comprising the following components in parts by weight: the battery has low potential, low capacity and long service life, and the battery performance is improved by making up for the deficiencies of Mn and Fe. Aluminum and/or magnesium are doped to partially replace the positions of Mn and Fe, so that the lattice substitution defect of the material is increased, the internal conductivity of the material is improved, the polarization degree in the charge-discharge process is reduced, and the refined crystal grains are more beneficial to Na + The electrochemical capacity and the cycle performance of the material are improved. The raw materials used in the invention do not contain noble metals, are cheap and easily available, but can ensure higher gram capacity and high voltage, and can improve the volumetric specific energy of the sodium-ion battery.
(2) The preparation method of the material adopts a mature gel method, adopts citric acid as a complexing agent, simultaneously adopts citric acid as a gelling agent, produces gel in the reaction process, generates a homogeneous precursor after drying, does not discharge and pollute the environment in the production process, and is environment-friendly. The gel is decomposed at high temperature to generate the carbon coating layer in situ, so that the electronic conductivity of the material can be further improved.
(3) The invention adopts cheap and easily available raw materials, has no pollutant discharge and no byproduct generation in the preparation process, and is a technology which is cheap, practical and suitable for large-scale popularization and application.
Drawings
FIG. 1 is a discharge curve chart of example 1 of the present invention.
FIG. 2 is a graph showing cycle life in example 1 of the present invention.
FIG. 3 is a discharge curve chart of example 2 of the present invention.
FIG. 4 is a discharge curve chart of example 3 of the present invention.
Fig. 5 is a charge and discharge graph of comparative example 1.
FIG. 6 is a graph comparing the discharge rates of example 10 and comparative example 2.
Detailed Description
Example 1
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x The formula of the synthetic material of this example is Na, where x is 1, a is 1.5, b is 1.49, and c is 0.01 4 Mn 1.5 Fe 1.5 Mg 0.01 (PO 4 ) 2 P 2 O 7 Selecting a sodium source as sodium hydroxide, selecting an iron source as iron powder, selecting a manganese source as manganese carbonate, selecting a doping element A as magnesium hydroxide, and selecting a phosphorus source as phosphoric acid; citric acid as gelling agent has chelating effect on metal particles, can generate uniform and stable precursor, and can be carbonized at fourth high temperature to obtain carbon-coated Na 4 Mn 1.5 Fe 1.5 Mg 0.01 (PO 4 ) 2 P 2 O 7 And the electronic conductivity of the material is improved.
The method for preparing the sodium-ion battery cathode material by using the gel method comprises the following steps:
(1) 461 g of 85 percent phosphoric acid, 1500 g of deionized water and 55 g of citric acid are weighed into a reaction kettle.
(2) Weighing 84 g of iron powder, 172.5 g of manganese carbonate and 0.58 g of magnesium hydroxide, adding into a reaction kettle, controlling the feeding time to be 3h, the reaction time to be 24h, the reaction temperature to be 80 ℃, and the rotating speed of the reaction kettle to be 1000 rpm.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into 10mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 30 minutes, controlling the reaction temperature to be 80 ℃, and controlling the rotating speed of the reaction kettle to be 1000 rpm.
(4) And (3) spray-drying the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 600 ℃, the time is 10 hours, and crushing the material subjected to heat treatment for 500 meshes and sieving to obtain the sodium-ion battery anode material.
The material prepared in the embodiment is used for preparing a positive pole piece of a sodium ion secondary battery after ball milling. The method comprises the following specific steps: mixing Na 4 Mn 1.5 Fe 1.5 Mg 0.01 (PO 4 ) 2 P 2 O 7 The powder, acetylene black and a binder polyvinylidene fluoride (PVDF) were mixed by NMP solvent in a mass ratio of 85: 10: 5, and the mixed slurry was coated on an aluminum foil and dried at 120 ℃ for 10 hours under vacuum for later use. The simulated button cell is carried out in an Ar gas glove box, the electrode adopts metallic sodium, the electrolyte adopts commercially available sodium ion battery electrolyte, and the CR2032 battery is assembled, the tested voltage range is between 1.5 and 4.1V, under the multiplying power of C/10, the first cycle charging specific capacity is 136 milliampere-hour/gram, and the discharging specific capacity is 116 mAh/g. The prepared batteries are respectively subjected to 0.1C, 0.2C, 0.5C, 1C, 2C, 5C and 10C rate discharge, a rate characteristic diagram is shown in figure 1, as can be seen from figure 1, the 10C discharge capacity of the invention is 77% of the 0.1C discharge capacity, and the rate characteristic of the material is better. The material obtained in example 1 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compacted density of 2.47g/cm 3 。
Example 2
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x Taking x as 0.8, a as 0.5, b as 2.07 and c as 0.02, the molecular formula of the synthetic material of this example is Na 4 Mn 0.5 Fe 2.07 Al 0.02 (PO 4 ) 2 (P 2 O 7 ) 0.8 Selecting a sodium source as sodium hydroxide, selecting an iron source as ferrous carbonate, selecting a manganese source as manganese carbonate, selecting an A doping element as aluminum hydroxide, and selecting a phosphorus source as ammonium dihydrogen phosphate; citric acid as gelling agent has chelating effect on metal particles, can generate uniform and stable precursor, and can be carbonized at fourth high temperature to obtain carbon-coated Na 4 Mn 0.5 Fe 2.07 Al 0.02 (PO 4 ) 2 (P 2 O 7 ) 0.8 And the electronic conductivity of the material is improved.
The method for preparing the sodium-ion battery cathode material by using the gel method comprises the following steps:
(1) 414 g of ammonium dihydrogen phosphate, 1700 g of deionized water and 100 g of citric acid are weighed and added into a reaction kettle.
(2) Weighing 240.1 g of ferrous carbonate, 57.5 g of manganese carbonate and 1.56 g of aluminum hydroxide, adding into a reaction kettle, controlling the feeding time to be 2.5h, the reaction time to be 30h, the reaction temperature to be 75 ℃, and controlling the rotating speed of the reaction kettle to be 600 r/min.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into a 5mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 45 minutes, controlling the reaction temperature to be 75 ℃, and controlling the rotating speed of the reaction kettle to be 600 revolutions per minute.
(4) And (3) carrying out spray drying on the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 620 ℃, and the time is 8 hours, and crushing the material subjected to heat treatment by using a 500-mesh sieve to obtain the sodium-ion battery anode material.
The material prepared in the embodiment is used for preparing a positive pole piece of a sodium ion secondary battery after ball milling. The method comprises the following specific steps: na is mixed with 4 Mn 0.5 Fe 2.07 Al 0.02 (PO 4 ) 2 (P 2 O 7 ) 0.8 Powder, acetylene black and binder polymerVinylidene fluoride (PVDF) was mixed with NMP solvent at a mass ratio of 85: 10: 5, and the mixed slurry was coated on aluminum foil and dried at 120 ℃ for 20 hours under vacuum for later use. The simulated button cell is carried out in an Ar gas glove box, the electrode adopts metallic sodium, the electrolyte adopts commercially available sodium ion battery electrolyte, and is assembled into a CR2032 battery and is assembled into the CR2032 battery, the tested voltage range is between 1.5 and 4.1V, under the multiplying power of C/10, the first cycle charging specific capacity is 140 milliampere-hour/gram, the discharging specific capacity is 101mAh/g, and the first effect of the battery is 81.4 percent. The material obtained in example 2 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compacted density of 2.52g/cm 3 。
Example 3
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x The formula of the synthetic material of this example is Na, where x is 0.9, a is 2, b is 0.88, and c is 0.04 4 Mn 2 Fe 0.74 Al 0.04 (PO 4 ) 2 (P 2 O 7 ) 0.9 . Selecting a sodium source as sodium carbonate, selecting an iron source as ferrous carbonate, selecting a manganese source as manganese carbonate, selecting an A doping element as aluminum hydroxide, and selecting a phosphorus source as ammonium dihydrogen phosphate; citric acid as gelling agent has chelating effect on metal particles, can generate uniform and stable precursor, and can be carbonized at fourth high temperature to obtain carbon-coated Na 4 Mn 2 Fe 0.74 Al 0.04 (PO 4 ) 2 (P 2 O 7 ) 0.9 And the electronic conductivity of the material is improved.
The method for preparing the sodium-ion battery cathode material by using the gel method comprises the following steps:
(1) 437 grams of ammonium dihydrogen phosphate, 2400 grams of deionized water and 90 grams of citric acid are weighed and added into a reaction kettle.
(2) Weighing 102 g of ferrous carbonate, 230 g of manganese carbonate and 3.12 g of aluminum hydroxide, adding into a reaction kettle, controlling the feeding time to be 2.2h, the reaction time to be 28h, the reaction temperature to be 70 ℃, and the rotating speed of the reaction kettle to be 800 rpm.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into a 4mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 50 minutes, controlling the reaction temperature to be 70 ℃, and controlling the rotating speed of the reaction kettle to be 800 r/m.
(4) And (3) carrying out spray drying on the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 680 ℃, and the time is 5 hours, and crushing the material subjected to heat treatment, and sieving the crushed material by a sieve of 500 meshes to obtain the sodium-ion battery anode material.
The material prepared in the embodiment is used for preparing a positive pole piece of a sodium ion secondary battery after ball milling. The method comprises the following specific steps: mixing Na 4 Mn 2 Fe 0.74 Al 0.04 (PO 4 ) 2 (P 2 O 7 ) 0.9 The powder, acetylene black and a binder polyvinylidene fluoride (PVDF) were mixed by NMP solvent at a mass ratio of 85: 10: 5, and the mixed slurry was coated on an aluminum foil and dried at 120 ℃ for 20 hours under vacuum for later use. The simulated button cell is carried out in an Ar gas glove box, the electrode adopts metallic sodium, the electrolyte adopts commercially available sodium ion battery electrolyte, and the CR2032 battery is assembled, the tested voltage range is between 1.5 and 4.1V, under the multiplying power of C/10, the first cycle charging specific capacity is 130 mAh/g, the discharging specific capacity is 103mAh/g, and the first efficiency of the battery is 83%. The material obtained in example 3 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compacted density of 2.43g/cm 3 。
Example 4
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x The formula of the synthetic material of this example is Na, where x is 1, a is 2.5, b is 0.49, and c is 0.01 4 Mn 2.5 Fe 0.49 Mg 0.01 (PO 4 ) 2 P 2 O 7 . Wherein the sodium source is selected as sodium carbonate, the iron source is selected as iron powder, the manganese source is selected as manganese carbonate, and the A doping element is selected asMagnesium hydroxide, wherein the phosphorus source is ammonium dihydrogen phosphate; citric acid as gelling agent has chelating effect on metal particles, can generate uniform and stable precursor, and can be carbonized at fourth high temperature to obtain carbon-coated Na 4 Mn 2.5 Fe 0.49 Mg 0.01 (PO 4 ) 2 P 2 O 7 And the electronic conductivity of the material is improved.
The method for preparing the sodium-ion battery cathode material by using the gel method comprises the following steps:
(1) 460 g of ammonium dihydrogen phosphate, 2000 g of deionized water and 95 g of citric acid are weighed into a reaction kettle.
(2) Weighing 56.8 g of ferrous carbonate, 287.5 g of manganese carbonate and 1.16 g of magnesium hydroxide, adding into a reaction kettle, controlling the feeding time to be 2.8h, the reaction time to be 40h, the reaction temperature to be 60 ℃, and controlling the rotating speed of the reaction kettle to be 1500 rpm.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into 6mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 60 minutes, controlling the reaction temperature to be 60 ℃, and controlling the rotating speed of the reaction kettle to be 1500 rpm.
(4) And (3) spray-drying the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 580 ℃, and the time is 8 hours, and crushing the material subjected to heat treatment for 500 meshes and sieving to obtain the sodium-ion battery anode material.
The material prepared in the embodiment is used for preparing a positive pole piece of a sodium ion secondary battery after ball milling. The method comprises the following specific steps: mixing Na 4 Mn 2.5 Fe 0.49 Mg 0.01 (PO 4 ) 2 P 2 O 7 The powder, acetylene black and a binder polyvinylidene fluoride (PVDF) were mixed by NMP solvent at a mass ratio of 85: 10: 5, and the mixed slurry was coated on an aluminum foil and dried at 120 ℃ for 20 hours under vacuum for later use. The simulated button cell is carried out in a glove box under Ar gas, the electrode adopts metallic sodium, the electrolyte adopts commercial sodium ion battery electrolyte, the CR2032 battery is assembled, the tested voltage range is between 1.5 and 4.1V, under the multiplying power of C/10, the first cycle charging specific capacity is 137 mAmp hour/g,the discharge specific capacity is 115mAh/g, and the first efficiency of the battery is 81 percent. The material obtained in example 4 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compacted density of 2.56g/cm 3 。
Example 5
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x The formula of the synthetic material of this example is Na, where x is 1, a is 2.2, b is 0.78, and c is 0.02 4 Mn 2.2 Fe 0.78 Mg 0.02 (PO 4 ) 2 P 2 O 7 . Selecting a sodium source as a mixture of sodium carbonate and sodium hydroxide, selecting an iron source as iron powder, selecting a manganese source as manganese carbonate, selecting an A doping element as magnesium carbonate, and selecting a phosphorus source as phosphoric acid; citric acid as gelling agent has chelating effect on metal particles, can generate uniform and stable precursor, and can be carbonized at fourth high temperature to obtain carbon-coated Na 4 Mn 2.2 Fe 0.78 Mg 0.02 (PO 4 ) 2 P 2 O 7 And the electronic conductivity of the material is improved.
The method for preparing the sodium-ion battery cathode material by using the gel method comprises the following steps:
(1) 85% phosphoric acid 461 g, deionized water 1600 g and citric acid 59 g were weighed into a reaction kettle.
(2) Weighing 90.5 g of ferrous carbonate, 253 g of manganese carbonate and 1.68 g of magnesium carbonate, adding into a reaction kettle, controlling the feeding time to be 3 hours, the reaction time to be 45 hours, the reaction temperature to be 68 ℃, and the rotating speed of the reaction kettle to be 650 rpm.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into a 3mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 55 minutes, controlling the reaction temperature to be 68 ℃, and controlling the rotation speed of the reaction kettle to be 650 r/min.
(4) And (3) spray-drying the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 590 ℃, the time is 10 hours, and crushing the material subjected to heat treatment for 500 meshes and sieving to obtain the sodium-ion battery anode material.
The material prepared in the embodiment is used for preparing a positive pole piece of a sodium ion secondary battery after ball milling. The method comprises the following specific steps: mixing Na 4 Mn 2.2 Fe 0.78 Mg 0.02 (PO 4 ) 2 P 2 O 7 The powder, acetylene black and a binder polyvinylidene fluoride (PVDF) were mixed by NMP solvent at a mass ratio of 85: 10: 5, and the mixed slurry was coated on an aluminum foil and dried at 120 ℃ for 20 hours under vacuum for later use. The simulated button cell is carried out in an Ar gas glove box, the electrode adopts metallic sodium, the electrolyte adopts commercially available sodium ion battery electrolyte, and the CR2032 battery is assembled, the tested voltage range is between 1.5 and 4.1V, under the multiplying power of C/10, the first cycle charging specific capacity is 132 milliampere-hour/gram, the discharging specific capacity is 117mAh/g, and the first efficiency of the battery is 79.5 percent. The material obtained in example 5 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compaction density of 2.5g/cm 3 。
Example 6
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x Taking x as 0.9, a as 1.8, b as 0.99, and c as 0.01, the molecular formula of the synthetic material of this example is Na 4 Mn 1.8 Fe 0.99 Mg 0.01 (PO 4 ) 2 (P 2 O 7 ) 0.9 . Wherein sodium source is selected from sodium hydroxide, iron source is selected from ferrous carbonate, manganese source is selected from manganese carbonate, A doping element is selected from magnesium carbonate, and phosphorus source is selected from phosphoric acid; citric acid as gelling agent has chelating effect on metal particles, can generate uniform and stable precursor, and can be carbonized at fourth high temperature to obtain carbon-coated Na 4 Mn 1.8 Fe 0.99 Mg 0.01 (PO 4 ) 2 (P 2 O 7 ) 0.9 And the electronic conductivity of the material is improved.
The method for preparing the sodium-ion battery cathode material by using the gel method comprises the following steps:
(1) 438 g of 85% phosphoric acid, 2200 g of deionized water and 64 g of citric acid were weighed into a reaction kettle.
(2) Weighing 114.8 g of ferrous carbonate, 207 g of manganese carbonate and 0.84 g of magnesium carbonate, adding into a reaction kettle, controlling the feeding time to be 2.6h, controlling the reaction time to be 32h, controlling the reaction temperature to be 72 ℃, and controlling the rotation speed of the reaction kettle to be 700 rpm.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into an 8mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 45 minutes, controlling the reaction temperature to be 72 ℃, and controlling the rotating speed of the reaction kettle to be 700 revolutions per minute.
(4) And (3) spray-drying the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 610 ℃, the time is 7 hours, and crushing the material subjected to heat treatment for 500 meshes and sieving to obtain the sodium-ion battery anode material.
The material prepared in the embodiment is used for preparing a positive pole piece of a sodium ion secondary battery after ball milling. The method comprises the following specific steps: mixing Na 4 Mn 1.8 Fe 0.99 Mg 0.01 (PO 4 ) 2 (P 2 O 7 ) 0.9 The powder, acetylene black and a binder polyvinylidene fluoride (PVDF) were mixed by NMP solvent at a mass ratio of 85: 10: 5, and the mixed slurry was coated on an aluminum foil and dried at 120 ℃ for 20 hours under vacuum for later use. The simulated button cell is carried out in an Ar glove box, the electrode adopts metallic sodium, the electrolyte adopts commercially available sodium ion battery electrolyte, and the CR2032 battery is assembled, the tested voltage range is between 1.5 and 4.1V, under the multiplying power of C/10, the first cycle charging specific capacity is 138 mAmp hour/g, the discharging specific capacity is 106mAh/g, the first efficiency of the battery is 81.9 percent, and the discharging curve chart is shown in figure 2. The material obtained in example 6 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compacted density of 2.48g/cm 3 。
Example 7
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x The formula of the synthetic material of this example is Na, where x is 1, a is 1, b is 1.99, and c is 0.01 4 MnFe 1.99 Mg 0.01 (PO 4 ) 2 P 2 O 7 . Selecting a sodium source as sodium carbonate, selecting an iron source as ferrous carbonate, selecting a manganese source as manganese carbonate, selecting an A doping element as magnesium carbonate and selecting a phosphorus source as phosphoric acid; citric acid as gelling agent has chelating effect on metal particles, can generate uniform and stable precursor, and can be carbonized at fourth high temperature to obtain carbon-coated Na 4 MnFe 1.99 Mg 0.01 (PO 4 ) 2 P 2 O 7 And the electronic conductivity of the material is improved.
The gel method is used for preparing the sodium ion battery anode material, and the steps are as follows:
(1) 85% phosphoric acid 461 g, deionized water 1900 g and citric acid 56g were weighed into a reaction kettle.
(2) 231 g of ferrous carbonate, 115 g of manganese carbonate and 0.84 g of magnesium carbonate are weighed and added into a reaction kettle, the feeding time is controlled to be 2.6h, the reaction time is controlled to be 32h, the reaction temperature is controlled to be 78 ℃, and the rotating speed of the reaction kettle is controlled to be 850 rpm.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into a 4.5mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 58 minutes, controlling the reaction temperature to be 78 ℃, and controlling the rotating speed of the reaction kettle to be 850 rpm.
(4) And (3) spray-drying the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 630 ℃, the time is 6 hours, and crushing the material subjected to heat treatment for 500 meshes and sieving to obtain the sodium-ion battery anode material.
The material prepared in the embodiment is used for preparing a positive pole piece of a sodium ion secondary battery after ball milling. The method comprises the following specific steps: mixing Na 4 MnFe 1.99 Mg 0.01 (PO 4 ) 2 P 2 O 7 Mixing the powder, acetylene black and polyvinylidene fluoride (PVDF) binder at a mass ratio of 85: 10: 5 with NMP solvent, coating the mixed slurry on aluminum foil, and vacuum-dryingDried at 120 ℃ for 20 hours under the condition for standby. The simulated button cell is carried out in an Ar glove box, the electrode adopts metallic sodium, the electrolyte adopts commercially available sodium ion battery electrolyte, and the CR2032 battery is assembled, the tested voltage range is between 1.5 and 4.1V, under the multiplying power of C/10, the first cycle charging specific capacity is 142 milliampere-hour/gram, the discharging specific capacity is 116mAh/g, the first efficiency of the battery is 81.7 percent, and the discharging curve chart is shown in figure 3. The material obtained in example 7 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compacted density of 2.51g/cm 3 。
Example 8
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn 1.2 Fe b A c (PO 4 ) 2 (P 2 O 7 ) x The formula of the synthetic material of this example is Na, where x is 1, a is 1.2, b is 1.79, and c is 0.01 4 Mn 1.2 Fe 1.79 Mg 0.01 (PO 4 ) 2 P 2 O 7 . Selecting a sodium source as sodium carbonate, selecting an iron source as ferrous carbonate, selecting a manganese source as manganese carbonate, selecting an A doping element as magnesium carbonate, and selecting a phosphorus source as a mixture of phosphoric acid and ammonium dihydrogen phosphate; citric acid as gelling agent has chelating effect on metal particles, can generate uniform and stable precursor, and can be carbonized at fourth high temperature to obtain carbon-coated Na 4 Mn 1.2 Fe 1.79 Mg 0.01 (PO 4 ) 2 P 2 O 7 And the electronic conductivity of the material is improved.
The method for preparing the sodium-ion battery cathode material by using the gel method comprises the following steps:
(1) 230.6 g of 85 percent phosphoric acid, 230 g of ammonium dihydrogen phosphate, 3000 g of deionized water and 68 g of citric acid are weighed into a reaction kettle.
(2) Weighing 207.6 g of ferrous carbonate, 138 g of manganese carbonate and 0.84 g of magnesium carbonate, adding into a reaction kettle, controlling the feeding time to be 3h, the reaction time to be 24h, the reaction temperature to be 70 ℃, and the rotating speed of the reaction kettle to be 750 revolutions per minute.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into 6.5mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 60 minutes, controlling the reaction temperature to be 70 ℃, and controlling the rotation speed of the reaction kettle to be 750 revolutions per minute.
(4) And (3) spray-drying the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 650 ℃, the time is 6 hours, and crushing the material subjected to heat treatment for 500 meshes and sieving to obtain the sodium-ion battery anode material.
The material prepared in the embodiment is used for preparing a positive pole piece of a sodium ion secondary battery after ball milling. The method comprises the following specific steps: mixing Na 4 Mn 1.2 Fe 1.79 Mg 0.01 (PO 4 ) 2 P 2 O 7 Acetylene black and a binder polyvinylidene fluoride (PVDF) were mixed by NMP solvent at a mass ratio of 85: 10: 5, and the mixed slurry was coated on an aluminum foil and dried at 120 ℃ for 20 hours under vacuum for later use. The simulated button cell is carried out in an Ar gas glove box, the electrode adopts metallic sodium, the electrolyte adopts commercially available sodium ion battery electrolyte, and the CR2032 battery is assembled, the tested voltage range is 1.5-4.1V, under the multiplying power of C/10, the first cycle charging specific capacity is 130 mAh/g, the discharging specific capacity is 118mAh/g, and the first efficiency of the battery is 83.8%. The material obtained in example 8 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compacted density of 2.46g/cm 3 。
Example 9
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x When x is 1, a is 2.4, b is 0.59, and c is 0.01, the formula of the synthetic material in this example is Na 4 Mn 2.4 Fe 0.59 Mg 0.01 (PO 4 ) 2 P 2 O 7 . Wherein the sodium source is selected as sodium hydroxide, the iron source is selected as ferrous carbonate, the manganese source is selected as manganese carbonate, the doping element A is selected as magnesium hydroxide, and the phosphorus source is selected as phosphoric acid; citric acid as gel has chelating effect on metal particles and can generateHomogenizing and stabilizing the precursor, and simultaneously carbonizing the precursor at a fourth high temperature to obtain carbon-coated Na 4 Mn 2.4 Fe 0.59 Mg 0.01 (PO 4 ) 2 P 2 O 7 And the electronic conductivity of the material is improved.
The method for preparing the sodium-ion battery cathode material by using the gel method comprises the following steps:
(1) 461 g of phosphoric acid, 2500 g of deionized water and 70 g of citric acid are weighed and added into a reaction kettle.
(2) Weighing 132 g of iron powder, 276 g of manganese carbonate and 0.58 g of magnesium hydroxide, adding into a reaction kettle, controlling the feeding time to be 2.4h, the reaction time to be 26h, the reaction temperature to be 77 ℃, and the rotating speed of the reaction kettle to be 500 rpm.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into a 5mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 52 minutes, controlling the reaction temperature to be 77 ℃, and controlling the rotation speed of the reaction kettle to be 500 r/min.
(4) And (3) spray-drying the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 580 ℃, the time is 10 hours, and crushing the material subjected to heat treatment for 500 meshes and sieving to obtain the sodium-ion battery anode material.
The material prepared in the embodiment is ground and then used for preparing a positive pole piece of a sodium ion secondary battery. The method comprises the following specific steps: mixing Na 4 Mn 2.4 Fe 0.59 Mg 0.01 (PO 4 ) 2 P 2 O 7 The powder, acetylene black and a binder polyvinylidene fluoride (PVDF) were mixed by NMP solvent at a mass ratio of 85: 10: 5, and the mixed slurry was coated on an aluminum foil and dried at 120 ℃ for 12 hours under vacuum for use. The simulated button cell is carried out in an Ar glove box, metal sodium is adopted for an electrode, commercially available sodium ion battery electrolyte is adopted for the electrolyte, the tested voltage range is 2.5-4.0V, under the multiplying power of C/10, the first-cycle charging specific capacity is 133 mAmp hours/g, the discharging specific capacity is 117 mAmp hours/g, and the first-cycle efficiency of the cell is 79.7%. The material obtained in example 9 was measured under 200MPa test conditions using a powder compaction density tester to determine the compactionThe solid density is 2.49g/cm 3 。
Example 10
The molar ratio of the elements according to the formula of this example corresponds to the molar ratio in the chemical formula of the invention: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x The formula of the synthetic material of this example is Na, where x is 1, a is 1.5, b is 1.48, and c is 0.02 4 Mn 1.5 Fe 1.48 Mg 0.02 (PO 4 ) 2 P 2 O 7 . Wherein the sodium source is selected as sodium hydroxide, the iron source is selected as ferrous carbonate, the manganese source is selected as manganese carbonate, the doping element A is selected as a mixture of magnesium hydroxide and magnesium carbonate, and the phosphorus source is selected as phosphoric acid; citric acid as gelling agent has chelating effect on metal particles, can generate uniform and stable precursor, and can be carbonized at fourth high temperature to obtain carbon-coated Na 4 Mn 1.5 Fe 1.48 Mg 0.02 (PO 4 ) 2 P 2 O 7 And the electronic conductivity of the material is improved.
The method for preparing the sodium-ion battery cathode material by using the gel method comprises the following steps:
(1) 461 g of 85 percent phosphoric acid, 2500 g of deionized water and 90 g of citric acid are weighed and added into a reaction kettle.
(2) Weighing 82.9 g of iron powder, 172.5 g of manganese carbonate, 0.58 g of magnesium hydroxide and 0.84 g of magnesium carbonate, adding into a reaction kettle, controlling the feeding time to be 2.8h, the reaction time to be 24h, the reaction temperature to be 75 ℃, and controlling the rotating speed of the reaction kettle to be 600 revolutions per minute.
(3) Weighing 160 g of sodium hydroxide, preparing the sodium hydroxide into 9mol/L aqueous solution, adding the aqueous solution into a reaction kettle, controlling the feeding time to be 45 minutes, controlling the reaction temperature to be 75 ℃, and controlling the rotation speed of the reaction kettle to be 600 revolutions per minute.
(4) And (3) spray-drying the product obtained in the third step, carrying out heat treatment under the protection of argon atmosphere, wherein the temperature of a hot spot is 550 ℃, and the time is 11 hours, and crushing the material subjected to heat treatment for 500 meshes and sieving to obtain the sodium-ion battery anode material.
The material prepared in this example was usedGrinding the mixture to prepare the positive pole piece of the sodium ion secondary battery. The method comprises the following specific steps: mixing Na 4 Mn 1.5 Fe 1.48 Mg 0.02 (PO 4 ) 2 P 2 O 7 The powder, acetylene black and a binder polyvinylidene fluoride (PVDF) were mixed by NMP solvent at a mass ratio of 85: 10: 5, and the mixed slurry was coated on an aluminum foil and dried at 120 ℃ for 24 hours under vacuum for later use. The simulated button cell is carried out in an Ar glove box, metal sodium is adopted for an electrode, commercially available sodium ion battery electrolyte is adopted for the electrolyte, and the CR2032 battery is assembled, the tested voltage range is 2.5-4.0V, under the multiplying power of C/10, the first cycle charging specific capacity is 137 mAmp hour/g, the discharging specific capacity is 118 mAmp hour/g, and the first efficiency of the battery is 82.5%. The material obtained in example 10 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compacted density of 2.49g/cm 3 。
Comparative example 1
Comparative example 1 preparation of manganese-containing oxygen Compound Na by solid phase method 0.44 MnO 2 The method is used for comparison as the positive electrode of the sodium ion secondary battery and comprises the following specific steps:
(1) respectively weighing Na according to the amount ratio of substances in the molecular formula 2 CO 3 24.2 g of Mn 3 O 4 76.3 g, wet grinding for 1 hour at 300 r/min by adopting alcohol as a dispersing agent in a zirconia ball milling tank, and drying to obtain precursor powder.
(2) Tabletting the precursor powder obtained in the first step under the pressure of 12MPa, and then transferring to Al 2 O 3 In a crucible, heat-treating at 850 deg.C for 10 hr in air atmosphere to obtain black material Na containing manganese oxide 0.44 MnO 2 。
The material prepared in the comparative example 1 is ground and used for preparing the positive pole piece of the sodium-ion secondary battery. The method comprises the following specific steps: mixing Na 0.44 MnO 2 The powder was mixed with acetylene black and a binder polyvinylidene fluoride (PVDF) at a mass ratio of 85: 10: 5 by NMP solvent, and the mixed slurry was coated on an aluminum foil and dried under vacuum at 120 ℃ for 24 hours for use. DieThe simulated button cell is carried out in a glove box under Ar gas, the counter electrode adopts metallic sodium, the electrolyte adopts a sodium ion battery electrolyte sold in the market, the tested voltage range is between 2.5 and 4.0V, and the first cycle charging capacity is 50 mAmp hours/g and the specific discharge capacity is 42 mAmp hours/g can be seen from figure 4.
Therefore, the positive electrode material provided in the embodiment of the invention has better performance than Na in the prior art when used as the positive electrode material of a sodium ion secondary battery 0.44 MnO 2 And (3) a positive electrode material.
Comparative example 2
Comparative example 2 a high temperature solid phase synthesis method was used to prepare a positive electrode material for a sodium ion battery, and comparative example 10 was used to prepare the positive electrode material for a sodium ion battery using a gel method, and the preparation method of comparative example 2 was:
(1) 160 g of sodium hydroxide, 82.9 g of iron powder, 172.5 g of manganese carbonate, 0.58 g of magnesium hydroxide, 1.68 g of magnesium carbonate, 461 g of 85% phosphoric acid, 2500 g of deionized water, 30 g of sucrose and 30 g of glucose are respectively weighed, the weighed raw materials are put into a reaction kettle for reaction, the reaction is carried out at the room temperature of 25 ℃ for 9h, the rotating speed of the reaction kettle is controlled to be 200-300 r/m, and in order to protect the materials from being oxidized by air in the reaction process, argon is introduced for protection.
(2) And (3) performing sand grinding dispersion on the reacted material, wherein the particle size of the material D50 dispersed by the sand grinding machine is 500 nm.
(3) And (3) carrying out spray drying on the sanded material, wherein the dried powder is a precursor, and carrying out heat treatment on the precursor powder for 14 hours at the temperature of 610 ℃ in an argon atmosphere to obtain the sodium-ion battery anode material.
According to the element mole ratio in comparative example 2, it corresponds to the formula: na (Na) 4 Mn a Fe b A c (PO 4 ) 2 (P 2 O 7 ) x Taking x as 1, a as 1.5, b as 1.48 and c as 0.02, the molecular formula of the synthetic material is Na 4 Mn 1.5 Fe 1.48 Mg 0.02 (PO 4 ) 2 P 2 O 7 . Wherein the sodium source is selected from sodium hydroxide, the iron source is selected from ferrous carbonate, the manganese source is selected from manganese carbonate, and A is dopedThe element is selected from a mixture of magnesium hydroxide and magnesium carbonate, and the phosphorus source is selected from phosphoric acid; in addition, the organic carbon source is selected from a mixture of sucrose and glucose, and the organic carbon source is used as a carbon coating agent and is carbonized under the high-temperature treatment of the third step to obtain carbon-coated Na 4 Mn 1.5 Fe 1.48 Mg 0.02 (PO 4 ) 2 P 2 O 7 And the electronic conductivity of the material is improved.
The material prepared in the comparative example 2 is ground and used for preparing the positive pole piece of the sodium-ion secondary battery. The method comprises the following specific steps: mixing Na 4 Mn 1.5 Fe 1.48 Mg 0.02 (PO 4 ) 2 P 2 O 7 The powder, acetylene black and a binder polyvinylidene fluoride (PVDF) were mixed by NMP solvent at a mass ratio of 85: 10: 5, and the mixed slurry was coated on an aluminum foil and dried at 120 ℃ for 24 hours under vacuum for later use. The simulated button cell is carried out in an Ar glove box, metal sodium is adopted for an electrode, commercially available sodium ion battery electrolyte is adopted for the electrolyte, and the CR2032 battery is assembled, the tested voltage range is 2.5-4.0V, under the multiplying power of C/10, the first cycle charging specific capacity is 137 mAmp-hr/g, the discharging specific capacity is 113 mAmp-hr/g, and the first efficiency of the battery is 82.5%. The material obtained in example 10 was measured using a powder compaction density tester under 200MPa test conditions to obtain a compacted density of 2.49g/cm 3 . The materials prepared in example 10 and comparative example 2 were respectively prepared into CR2032 batteries, and subjected to comparative tests of 1C, 2C, 5C and 10C rate, as shown in fig. 6, the positive electrode material prepared by the gel method in example 10 of the present invention has better discharge rate performance than the positive electrode material prepared by the high temperature solid phase method in comparative example 2.
Detection example 1
The data of the tests in the above examples and comparative examples are shown in tables 1 and 2.
TABLE 1 comparative table of discharge capacity of inventive examples and comparative examples
Table 2 table comparing the compacted densities of inventive examples and commercial positive electrode materials
| Compacted density (g/cm) at 200MPa 3 ) | |
| Example 1 | 2.51 |
| Example 2 | 2.52 |
| Example 3 | 2.49 |
| Example 4 | 2.53 |
| Example 5 | 2.5 |
| Example 6 | 2.49 |
| Example 7 | 2.51 |
| Example 8 | 2.48 |
| Example 9 | 2.49 |
| Example 10 | 2.49 |
| Commercial Prussian blue sodium ion cathode material | 1.5 |
| Commercial sodium vanadium phosphate | 2.2 |
The comparative results of the discharge capacity in each example and comparative example are shown in table 1, and the 0.1C first charge capacity and the 0.1C first discharge capacity in each example are both greatly improved compared with comparative example 1 and are not much different from those in comparative example 2; however, comparative example 2, which was prepared using a high-temperature solid-phase synthesis method, was slightly lower than comparative example 1 for the first efficiency of the battery, and in the case where each example was prepared using a gel method, it was significantly improved over both comparative example 1 and comparative example 2.
The compaction density comparison result is shown in table 2, the compaction density of the positive electrode material of the sodium-ion battery prepared in each example is about 2.5g/cm3, and the positive electrode material reaches the equivalent compaction density level of a commercial lithium iron phosphate material and is higher than that of a prussian blue compound material and a vanadium sodium phosphate material, so that the volumetric specific energy of the sodium-ion battery can be improved.
Claims (10)
1. The sodium-ion battery positive electrode material prepared by a gel method is characterized by comprising the following steps:
(1) adding a phosphorus source, a gelling agent and deionized water into a reaction kettle,
wherein the mass ratio of the gelling agent to the phosphorus source is 1-2: 9;
(2) adding an iron source, a manganese source and a doping element source into the reaction kettle in the step (1), and carrying out mixing reaction under the protection of inert atmosphere;
(3) preparing a sodium source into a solution, adding the solution into the reaction kettle reacted in the step (2), and carrying out mixed reaction under the protection of inert atmosphere;
(4) spray drying the reaction product obtained in the step (3) to obtain a precursor, carrying out heat treatment on the precursor under the protection of inert atmosphere to obtain the sodium-ion battery anode material,
wherein the molar ratio of sodium element, manganese element, iron element, doping element source and phosphorus element in the sodium source, manganese source, iron element, doping element and phosphorus source is 4: 0.5-2.5: 0.49-2.07: 0.01-0.04: 3.6-4.
2. The positive electrode material for sodium-ion batteries according to claim 1, characterized in that said gelling agent is citric acid.
3. The positive electrode material for the sodium-ion battery as claimed in claim 2, wherein 2.27-5.88 g of gelling agent is added to every 100ml of deionized water in the step (1).
4. The positive electrode material for sodium-ion batteries according to claim 1,
the phosphorus source is at least one of phosphoric acid and ammonium dihydrogen phosphate;
the iron source is at least one of iron powder and ferrous carbonate;
the manganese source is manganese carbonate;
the doping element source is at least one of magnesium hydroxide, aluminum hydroxide, magnesium carbonate and aluminum carbonate;
the sodium source is sodium hydroxide.
5. The positive electrode material for the sodium-ion battery according to claim 1, wherein in the step (2), the feeding time is controlled to be 2-3 hours, the reaction time is controlled to be 24-48 hours, the reaction temperature is controlled to be 60-80 ℃, and the rotating speed of a reaction kettle is 200-2000 rpm.
6. The sodium-ion battery positive electrode material as claimed in claim 1, wherein in the step (3), the molar concentration of the sodium source is controlled to be 1-20 mol/L, the feeding time is controlled to be 30-60 minutes, the reaction temperature is controlled to be 60-80 ℃, and the rotation speed of the reaction kettle is 200-2000 rpm.
7. The positive electrode material for the sodium-ion battery according to claim 1, wherein in the step (4), the temperature of the heat treatment is 500-680 ℃, and the time is 5-20 h.
8. The positive electrode material for sodium-ion batteries according to claim 1, wherein in each step, the inert atmosphere is an argon atmosphere or a nitrogen atmosphere.
9. The positive electrode material of the sodium-ion battery prepared by the preparation method of any one of claims 1 to 8.
10. Use of the positive electrode material for sodium-ion batteries according to claim 9 for the preparation of sodium-ion batteries.
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| CN108046231A (en) * | 2017-11-13 | 2018-05-18 | 中南大学 | A kind of sodium-ion battery positive material and preparation method thereof |
| CN108987722A (en) * | 2018-08-10 | 2018-12-11 | 佛山腾鲤新能源科技有限公司 | A kind of preparation method of new energy positive electrode for battery material |
| CN114530594A (en) * | 2021-12-27 | 2022-05-24 | 杭州华宏通信设备有限公司 | High-conductivity long-cycle lithium iron phosphate battery and preparation method thereof |
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| CN104466129A (en) * | 2014-11-05 | 2015-03-25 | 西北大学 | Method for preparing lithium ion battery composite positive electrode material (lithium iron phosphate/tetraphenyl porphyrin magnesium) |
| CN108046231A (en) * | 2017-11-13 | 2018-05-18 | 中南大学 | A kind of sodium-ion battery positive material and preparation method thereof |
| CN108987722A (en) * | 2018-08-10 | 2018-12-11 | 佛山腾鲤新能源科技有限公司 | A kind of preparation method of new energy positive electrode for battery material |
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